Hydraulic power shovel



June 18, 1935. w, w SLQANE 2,005,482

HYDRAULIC POWER SHOVEL Filed Sept. '25, 1931 4 Sheets-Sheet 1 June 18, 1935. v w. w. SLOANE 2,005,432

HYDRAULIC POWER SHOVEL Filed Sept. '25, 1931 4 Sheets-Sheet 3 0 a J In A 6 w a w m m 6 0 6 o a 6 Z 5% m i i Ov Q J W. "I u .T/ M 7 w flyw i 5 J W n z J a v0 6 0 0; I. L 3 0 g u 5 J w @w "w u 6 .L m h n "J n r c. V W 0% MW t atet 31$, 33%

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WillBiaxn' W. Sloane, Chicago, Ill., asslgnor, by mesne assignments, to La Locomotive Works,

Incorporated, Virginia a, while, a corporation of Application September 25, 1931. Serial No. 565,015

. machines such as power shovels, cranes and the like, and more particularly to machines of the character described wherein certain of the parts are hydraulically actuated and controlled. The principal object of the invention is to provide an improved hydraulic operating system including a continuously operating pump, wherein means are provided for automatically unloading the pressure in the system during periods when the main hydraulic actuating devices are not in operation.

A further object is to provide means for supplying pressures of difiering values for different purposes, a higher pressure for the main hydraulic actuating devices, and a lower pressure for the hydraulic controlling devices such as clutch and brake operating plungers.

The invention may best be understood by reference to the accompanying drawings, in which Figure-1 is a view in side elevation of a power shovel constructed in accordance with my invention.

Figure 2 is an enlarged plan view illustrating the platform and a portion of the dipper operating mechanism shown in Figure 1.

Figure 3 is a diagram showing the main parts of the hydraulic system forming a part of my invention.

Figure 4 is a detail sectional view of a low pressure hydraulic plunger suitable for operating certain control devices such as clutches and brakes.

Figure 5 is an enlarged detail section of the unloading valve. I

Referring now to details of the embodiment i of my invention illustrated in the drawings, the

novel features are shown as applied to a power shovel having a. prime mover and the main operating parts carried on a frame or tum table I, pivotally mounted to swing in a horizontal plane on a base 2, said base being provided with suitable propelling mechanism such as an endless tread mechanism 3. The shovel 4 is of the dipper type having a handle 5 provided with a rack t engaging a pinion 1 driven through gears l and pinion l on shaft 1 of a hydraulic motor 9 mounted on the boom 8. The dipperl is further connected for operation .by means of a single cable '16 passing over a sheave I! on the outer end of boom 8 and wound on a main operating a drum lB.

The boom is arranged as usual at the front end of the platform so as to be raised or lowered by suitable draft means, herein comprising a cable it wound about sheaves H and I2 carried on the end of the boom and on a frame support I 3, respectively, and having one end wound on drum i5 on the platform. Power actuating and controlling means for said drum is provided in any suitable manner.

The driving motor 20 is of "the usuaI multi-.

cylinder hydrocarbon type mounted on a transverse axis at the rear of the platform. The main drive shaft 23 of the motor is connected through a pinion i9 and gear 22 to a jack shaft 23 in front of the motor. This shaft is arranged to drive a hydraulic pump 25 of any suitable form,

the pump herein shown being 01' the reciproc'at- 2 ing type having three radially disposed cylinders, and provided with an outlet 25' and inlet 25 1 The shaft 23 also has operative connections for driving the main power drum l8 through pinion 26, gear 271 on shaft 28, gear 29 on shaft 30, and a clutch M, at the opposite end of said shaft, affording selective driving engagement between said shaft and drum l8 normally mounted loosely thereon. Operative connections are also afiorded for driving the endless tread device 3 on the truck 2, herein consisting of a gear 35, operatively connected to the shaft 23 through gears 29, 21, 22, and loosely mounted on shaft 35. Reversible power connections are mounted on the shaft 36 herein consisting of a sliding clutch member 31, adapted to be connected with a pair. of oppositely connected gears 38 and 39', adapted to drive beveled gear 40 in opposite direction. Said beveled.

gear is mounted on the upper end of a vertically disposed shaft 4| concentric with the axis of movement of the turntable or main frame i. Suitable drive connections are afforded between the shaft 4! and the endless tread 3 on the truck. As will be seen in Figure 2 the endless tread device may be driven in either direction by shaft clutch member 31 to engage either beveled gears 38 and 39 with shaft 36. A clutch member 48 is mounted on the end of clutch 31 to engage and disengage shaft 36 from drive gear thereon, at will.

Referring now to the hydraulic actuating and control devices which are utilized in connection with the parts above described, the main hydraulic pump 25 has an outlet or high pressure pipe 50 and an inlet or supply pipe 5! leading from a storage or low pressure tank 52. A low pressure pipe 53 is connected to the storage tank 52. A safety valve 54 is preferably connected between the high and low pressure lines, as is best indicated in the diagram, Figure 3. A pressure tank or dome 64 partially filled with air is preferably connected in the high pressure line 50.

- Means for providing the crowding motion 'to the dipper handle comprises the hydraulic motor 9,

similar in construction to the hydraulic pump 25, but now used as a motor, and connected between the high and low pressure lines 55 and 53 by pipes gal and 9 through swivel joints as and iii disposed on the horizontal or the hinged boom and from thence through pipes t2 and respectively, the former or which is connected to valve 9 of any suitable form for controlling the pressure to the motor A similar motor is provided for swinging the turntable l on its base 2, said motor being connected across the high and low pressure lines 55 and and controlled by valve 58. lhis valve is preferably reversible and may be of the wellknown rotatable four way type, with reversing pipe lines 56 and til between the motor and valve, and a waste pipe 65 leading to the low pressure line The shaft 55 of motor 65 drives a pinion '38 meshed with gear ll loosely mounted on shaft 28, and having a bevel gear "it carried therewith, driving a bevel gear l2 on upright shaft 'l l. Said upright shaft has a pinion l t meshed with a circular rack M on the base, as seen in Figure 1. This swinging movement may be in either direction because of the reversibility of motor 65 as described.

Referring now to the means for automatically unloading the pressure in the system during periods when the main operating motors 9 and 65 are not in operation, the unloading system is best illustrated in the diagram in Figure 3. A cross line l5 affords connection between the high pressure line 5% and the low pressure line 53, communicatiori through said cross line being controlled 1 through a manually operated valve l6 and an automatic pressure responsive valve W.

The valve it is held in open position by spring l6 to permit unloading of the system, excepting when it is desired to use the full pressure available for the main operating motors, 9 and 55. Accordingly an interlocking connection is provided between the valves 9 of the motor 9 and the valve 68 of motor 65, so that when either of said valves is open, the master valve l6 will be closed. In the form shown, this interlocking connection consists of a rocker arm 99 adapted to engage the upper end of the valve stem 76 of valve '35, and having a rod H18 connected to its upper end, which rod carries a plurality of stops ml, ltll selectively engageable by cams 502, M13 carried on the valve handles of each of the valves 9 and 68. The arrangement is such that as soon as either of the valves 9 or 58 is in open position, the cam :02 or 533 will engage the respective stops till so as to move the master valve '16 into closed position. At all other times, when pressure is not being used for the main operating motors 9 and 65, the valve 56 is maintained in open position to permit unloading of the system, as will now be described.

Details of the unloading valve are shown in Figure 5. Said valve consists of a casing l8 having three cylindrical chambers 19, 8G and 8t, forming parts of valve members A, B and C, connected by a cross passage 82 at adjacent ends of said chambers. The two outside chambers '89 and 85 of valve members A and C have restricted valve ports 19 and ill closed by valve stems 79 and 8!, respectively. The valve stem lil is normally held open by compression spring 83, while the valve stem li is held closed by compression spring 86, the spring 83 being slightly weaker than the spring 8%. The central valve chamber 88 of valve B has an intermediate poppet valve member 85 on stem 86. A piston 81 at the upper end of said stem is reciprocably mounted in the upper end of the cylinder with its upper face open to the passage 82 so as to be responsive to pressure therein. The valve 35 is normally held closed by spring tit.

When the valve '56 in cross line '85 is open, pressure from the pump is communicated to each one of the three valve cylinders '69, St and El as follows: The pipe l5 communicates with the lower end of cylinder 58 below valve 25, and also communicates with a branch pipe 9i through a one way check valve Said branch. pipe Ell communicates with the upper end of the cylinder 8i and also through an extended line to the lower end of cylinder lb. A pi; branches oil the connecting pipe hi to a t ssure tank hereinafter referred to as the intermediate pressure tank, the purpose of which will hereinafter more fully appear.

A discharge passage $6 is formed in the valve casing ii and communicates with the valve chamber l9 above the piston l9 of valve stem lll through port 96 while a similar port 96 extends in the opposite direction and communicates with the adjacent valve cylinder 80 between the valve 35 and the piston 81 therein. The" discharge passage 98 communicates with pipe 96 leading direct to the low pressure line 53. A passage 91 communicates between the valve chamber 80 between valve 85 and piston 87 and the adjacent valve chamber ill below the piston ill of valve stem Bi As has already been suggested, the master valve 75 controlling the unloading cross line 65 is normally held open by spring 36 When the main operating motors 9 and 58 are not in use and the pump 25 is being operated, pressure builds up in the high pressure line 50 and communicates through valve 76, pipe 75, the one-way check valve 92 and branch pipes 90 and SI to the lower end of valve cylinder 59 and the upper end of valve cylinder 8|. Pressure is also communicated through the one-way check valve 92 to the lower end of valve cylinder 80, but the valve is normally held in closed position by spring 88.

As will be seen in Figure 5, the valve stem 59 is normally open while valve stem 8 I is normally closed. As pressure builds up in the valve chamber 79, the spring 83 being slightly weaker than the spring 84 closes valve A; a slight increase in pressure on valve C then opens the latter, admitting the pressure to the upper chamber 82 where it is effective upon the piston 81 so as to open the valve 85. This permits the fluid to flow through the valve 85 and unload through passage 98 and outlet passage 96 to pipe 96 direct to the low pressure'line 53.

The critical pressure at which the unloading takes placeis maintained in the intermediate pressure tank 95. In the event that the master valve is is closed so as to shut off pressure from the cross line, pressure may be maintained in the intermediate tank by the automatic shutting of the unloading valve system as follows:

As soon as pressure lowers to the critical point, valve C will close and valve A will open, releasing the pressure from the upper cylinder 82 and piston 81 communicating therewith. The spring 88 in the valve B will then close valve 85, thereby discontinuing any further escape of fluid to the low pressure line and diverting any additional flow into the intermediate pressure tank until aoceaee through line W.

I find it practical and desirable to fix the critical pressure of the unloading system at a value much less than the working pressures available for the main operating motors 9 and 65. For instance, in a power shovel of the character described, the usual working pressure for said main operating motors may be approximately 1000 pounds per square inch, while the critical pressure for operating the unloading valve may be in the neighborhood of 200 pounds per square inch. With the working pressure as thus indica ted, it will be understood that the intermediate pressure tank and associated lines will normally be subject to a much lower pressure than that maintained in the high pressure line.

I utilize this reduced pressure available in the intermediate pressure tank for the operation of auxiliary control devices such as means for shifting the clutches and setting the brakes of the power shovel. As shown in Figure'2 and the diagram of Figure 3, a low pressure pipe line i is connected to the intermediate pressure tank 95, and branch lines Hi6 and H11 lead to a clutch operating valve we and a brake operating valve I01 respectively. Said clutch and brake operating devices Hi6- and H11 associated with valves I06 and I01, are of the usual reversible plunger type shown in detail in Figure 4. A similar low pressure operating device I08 may be also used for tripping the dipper latch, as indicated in Figures 1 and 2.

Since the clutch and brake operating devices equire far less energy than the main operating motors 9 and 65, the pipe lines supplyingsaid devices may be much smaller than those of the high pressure lines. Furthermore, the pressure in the intermediate tank will be maintained fairly constant regardless of excessive fluctuations in the high pressure lines during operationof the main operating motors 9 or 65. Although the working pressure in the intermediate pressure tank 95 will be reduced'slightly from time to time by use of the auxiliary control devices, yet the pressure will be intermittently restored to its maximum each time the unloading system is operated during the frequent periods of inoperationbf themain operating motors 9 and 65.

Although I have illustrated and described one particular embodiment of my invention, it will be understood that I do not wish to be limited to the exact construction shown and described, but that various changes and modifications may be made without departing from the spirit and scope of my invention.

I claim:

1. In a machine of the character described, a prime mover, a hydraulic pump driven by said prime mover, a high pressure line, a low pressureline, hydraulic power devices connected between said high and low pressure lines, a by-pass line connected between said high and low pressure lines and having a pressure-responsive valve therein, a pressure tank connected to said high pressure line, and a pipe leading from said tank to said pressure-responsive valve and supplying pressure to open the latter when the pressure in said tank exceeds a predetermined value, and other hydraulic power devices connected between said pressure tank and said low pressure lines.

2. In a machine of the character described, a prime mover, a hydraulic pump driven by said prime mover, a high pressure line, a low pressure line, hydraulic power devices connected between said high and low pressure lines, a by-pass line connected between said high and low pressure lines and having a manually operable valve and a pressure-responsive valve therein, a pressuretank connected to the line between said valves and a pipe leading from said tank to said pressure-responsive valve adapted to supply pressure to open the latter at a predetermined pressure in saidtank, and other hydraulic power devices connected between said pressure tank and said low pressure line.

3. In a power shovel, a frame, a boom, a dipper thereon including a reciprocably movable handle and thrust mechanism therefor, a cable drum on said frame having flexible cable connections with said dipper, a constant speed engine on said frame having optional driving connection with said cable drum, a hydraulic pump driven by said engine, a high pressure line and a low pressure line, a hydraulic motor for said thrust mechanism between said high and low pressure lines, a bypass line between said latter lines having a manually controlled valve and a pressure-responsive valve therein, a pressure tank connected to said by-pass line between said valves, a pipe leading from said tank to said pressure-responsive valve adapted to supply pressure to open the latter at a predetermined pressure in said tank, and hy-' W. SLOANE. 

